PUBLIC HEALTH ASSESSMENT
SAND GRAVEL AND STONE SITE
ELKTON, MARYLAND
The Maryland Sand, Gravel and Stone (MSGS) National Priorities List (NPL) Site is located near Elkton in Cecil County, Maryland. Hazardous chemical wastes were dumped on the site from 1969 to 1974. Chemical liquids and sludges were originally disposed of in three open lagoons and were also buried on-site in drums. About 200,000 gallons of sludges and liquid wastes were removed from the site in 1975 and 1976. Contaminants that have been identified include many common volatile organic solvents and several heavy metals. Included in this group are several chemicals that are classified by the U.S. Environmental Protection Agency (EPA) as known human carcinogens and a number of others that EPA has classified as probable human carcinogens.
EPA has divided the site investigation and clean-up work into three phases. The Phase I Remedial Investigation and Feasibility Study (RI/FS) of the site was conducted in 1985 and focused on the characterization of contamination in the Eastern Excavated Area (EEA). High concentrations of contaminants were identified in on-site sediments, surface water, and shallow groundwater. Major contaminants include arsenic, cadmium, di(2-ethylhexyl)phthalate, chlorobenzene, ethylbenzene, methylene chloride, tetrachloroethylene, toluene, 1,1,1-trichloroethane, and trichloroethylene. Phase I remediation plans include the installation of a water treatment system to treat groundwater that is collected in on-site interceptor trenches. Buried drums, some of which still contained hazardous wastes, were removed from the site following the Phase I investigation. Contaminants have also moved into deeper groundwater in the EEA.
A barbed wire-topped, chain-link fence was constructed around the EEA in December 1988 and because of soil erosion, was further modified in June 1990. A 24-hour-a-day guard has also been posted at the site.
Contaminants have migrated from the EEA through the air, surface water, and groundwater. In the past, people who entered the site may have been exposed to contaminants in air or by direct contact with surface waters or sediments. The closest residences are located within about 1,000 feet of the EEA. During the spring and summer of 1976 and 1979, respectively, local residents complained of strong, site-related odors and associated health effects. People may also have been exposed by direct contact with contaminated sediments and surface water in Mill Creek, which receives surface water drainage from the site. Site investigators noted in the mid-1970s that the stream was severely polluted by site contaminants. A bioassessment of the creek that was conducted in 1988 did not find any indications of pollution.
The Phase II Remedial Investigation was designed to investigate possible waste disposal in the Western Excavated Area (WEA) and contamination of deep groundwater systems. Based on the results of the Phase II investigation, it was concluded that hazardous wastes were not disposed of in the WEA. Low concentrations of some organic chemicals were found in deep groundwater in the WEA. These chemicals appear to have migrated in a southerly direction (the general direction of groundwater flow) from the EEA. The testing of private wells surrounding the site showed no indication of site-related contamination, although contamination has been detected in wells, primarily in a private well west of the site. The Record of Decision (ROD) for Phase II requires periodic sampling of both on-site and off-site wells and, if necessary, point-of-use water treatment. Phase III will address contaminated soils in the EEA, site closure, and post closure activities. As of December 17, 1993, four quarterly sampling events of on-site and off-site wells had been completed. Low levels of volatile organic compounds continue to be found in the residential well west of the site. The resident is supplied bottled water.
No health-related concerns regarding the site have been expressed by local residents at two public meetings that were held near the site in 1989 and 1990. A review of available health outcome data for Cecil County did not reveal any increased rate of cancer mortality for recent years (compared to the State as a whole), but did show an increased frequency of two birth defects. This finding cannot be related to the site.
It is concluded that the MSGS site was a public health hazard in the past, during the period in which trespassers had unrestricted access to areas of high surface contamination. The site currently is classified as posing no apparent public health hazard, although there is the potential for the future contamination of off-site drinking water wells that are downgradient from the site if site remediation is not implemented.
Recommended actions include the following: regular monitoring of off-site wells, additional sampling of on-site surface soils and off-site sediments, and control of dust generation during remediation activities.
To determine if public health actions are needed, the Agency for Toxic Substances and Disease Registry's (ATSDR) Health Activities Recommendation Panel (HARP) has evaluated the data and information developed in the Maryland Sand, Gravel, and Stone Public Health Assessment. Because there are no indications that people have been exposed to contaminants at levels that may cause illness or disease, HARP determined that no follow-up health actions are indicated at this time. If the commenters express concerns during the public comment period, the Agency will consider programs to provide the residents with information about the public health assessment and their potential for exposure to site contaminants. If new information becomes available indicating exposure at levels of concern, ATSDR will evaluate that information to determine what actions, if any, are necessary.
To ensure that public health issues are addressed, the Maryland Department of the
Environment
(MDE) and ATSDR developed a public health action plan. MDE will communicate with local
residents to provide information and assistance in understanding their potential for exposure to
hazardous substances. MDE will also contact EPA to determine when and if recommendations
made in this public health assessment are to be implemented.
A. SITE DESCRIPTION AND HISTORY
The Maryland Sand, Gravel and Stone (MSGS) site (formerly Maryland Sand and Gravelstone) is located in Cecil County, Maryland, about 3 miles west of the town of Elkton. The site covers about 200 acres and lies within a triangle formed by Maryland Highway 40 (Pulaski Highway) to the south and Marley and Nottingham roads to the east and west, respectively (Figure 1). Surface water and wetlands on the site include three ponds (P01, P02, P03); the Sedge Meadow Area; a swamp; the Old Sedimentation Pond; and an upper reach of the western tributary of Mill Creek (Figure 2). The eastern tributary to Mill Creek lies about 1,000 feet east of the site and flows south. Mill Creek flows to the east-southeast, eventually draining into Little Elk Creek, which then joins Big Elk Creek.
The MSGS site was operated as a sand and gravel quarry. Materials were removed from two areas: the Eastern Excavated Area (EEA) and the Western Excavated Area (WEA) (Figure 2). About 3 acres in the EEA were used for disposal of waste-processing water, sludge, and drums of solid and semi-solid waste between 1969 and 1974. Three pits in the area were used as surface impoundments, where about 700,000 gallons of wastes were disposed. The two principal generators of waste were the Galaxy Chemical Company of Elkton, Maryland, a company that recycled solvents, and Air Products and Chemicals, Inc., a disposer of waste from latex production. MSGS was never licensed for on-site disposal of chemical wastes (1).
In April 1974, a pool of chemical waste burned on the MSGS site and gave off dense smoke (2). Later in 1974, the Maryland Department of Natural Resources (DNR) issued an order to cease disposal operations and clean up the site. During this same year, the DNR and the U.S. Environmental Protection Agency (EPA) conducted a biological assessment of a tributary of Mill Creek that receives drainage from the site (1,2). The agencies concluded that site contaminants were having a severe, adverse effect on the plants and animals in the creek. biological monitoring of the creek, which was conducted by DNR in 1975 and 1976, identified adverse effects up to 1 mile downstream of the site. These effects were attributed to site-related contaminants. Inspectors from DNR who were monitoring the site in 1976 noted strong odors and eye irritation from contact with airborne contaminants (1).
In 1975 and 1976, 200,000 gallons of liquid waste were removed from the site and shipped to a landfill in New Jersey. During this time period, sludges and drums of waste were buried in the EEA in clay-lined pits. In 1976, local residents filed a suit against Galaxy Chemicals Company and Maryland Sand and Gravelstone Company for alleged damages resulting from odors emitted from the site (1,2).
In 1979, EPA and Maryland DNR officials inspected the site and obtained samples of soil, surface water, and shallow groundwater. In 1980, the Maryland Department of Health and Mental Hygiene (DHMH) established 5 groundwater monitoring wells in the EEA. In 1982, Ecology and Environment, Inc., was contracted by EPA to conduct a preliminary assessment and site inspection at MSGS. Samples of on-site groundwater and surface water were analyzed as part of this investigation. Water samples from 4 off-site residential wells were also sampled and analyzed as part of the preliminary assessment (1).
The site was proposed for inclusion on the National Priorities List (NPL) in December 1982, and was added to the list in September 1984. The NPL is a list of all Superfund hazardous waste sites in the United States. Sites are added to the list if they achieve a certain score based on a ranking system that is applied to all potential Superfund sites. Once a site is added to the Superfund list, a series of mandatory steps are initiated that eventually lead to site clean-up. The first step is the completion of a Remedial Investigation/Feasibility Study (RI/FS) which involves a determination of the nature and extent of site contamination and a detailed analysis of remedial (clean-up) alternatives. Following completion of the RI/FS, EPA issues a Record of Decision (ROD) in which they select one of the remedial alternatives proposed for the site.
The Phase I RI/FS was completed in September 1985, and a Record of Decision (ROD) for Phase I was issued on September 30, 1985. The clean-up remedy for Phase I provided for: 1) the removal of buried material; 2) the construction of a fence around the most heavily contaminated portions of the EEA as part of remedial work outlined in an April 1988 Consent Decree; and 3) the installation of shallow groundwater interceptor trenches to collect the contaminated groundwater and leachate for treatment at a treatment plant to be built on site (3).
Portions of this phase which have been completed include: 1) removal of an estimated 1,200 steel drums of waste and 2 cement mixers containing waste; 2) installation of a fence around the EEA (completed in 1988); and 3) initiation of a treatability study to determine the location and type of groundwater collection and treatment system.
A ROD for Phase II was issued in September 1990. The remedy that was chosen includes a regular schedule of on-site and off-site groundwater monitoring (4). On-site monitoring will include groundwater from the middle sand, lower sand, and bedrock units. Off-site monitoring will be conducted using 4 private wells that were selected to maximize the likelihood of detecting any contaminants from the MSGS site. These wells are currently providing potable water to both residences and businesses. On-site and/or off-site point-of-use water treatment will be used if it is determined to be necessary (e.g., if contaminants reach an off-site well in concentrations that exceed drinking water standards or guidelines). As of December 17, 1993, 4 new monitoring wells have been drilled in the EEA: 4 are drilled into the middle sand unit, and 1 is drilled into the lower sand unit. Four quarterly sampling events for on-site and off-site wells have been completed. The results are discussed in the Environmental Contamination and Other Hazards section of this document. A borehole investigation has been completed at possible locations of 3 interceptor trenches for groundwater in the upper sand unit. Additionally, EPA has notified the Potentially Responsible Parties (PRPs) that a removal action for buried sludge may be pending. EPA is currently developing an order requiring removal of buried sludge.
One of the objectives for Phase II was to determine whether waste disposal had occurred in the WEA. The results of geophysical studies, surface soil sampling, and the shallow boring analysis conducted in the WEA indicate that waste disposal did not occur in this area (5). Based on these findings, no further investigation nor remedial activity should be necessary for the WEA. Phase III, the final phase of the RI/FS, will address contaminated soils in the EEA, site closure, and post-closure activities. A separate proposed plan will be issued in the future when the remedial investigation associated with Phase III is completed.
A Preliminary Health Assessment for the MSGS site was completed by MDE, in cooperation with ATSDR, in February 1989 (6). In the report, MDE recommended that measures be taken during the site remediation process to prevent the inhalation of contaminants (volatilized or adhering to particulates) by workers or nearby residents.
Staff from MDE's risk assessment office initially visited the site in November 1988 and a follow-up visit was made on October 8, 1991. The October visit was made by Peter Ashley and David Healy of MDE in the company of Charles Smyser, an employee of the Cecil County Health Department, and George Murray, the site manager for Clean Sites. Clean Sites has been hired by the Potential Responsible Parties (companies that have been identified as disposing of hazardous materials on the site) to coordinate the RI/FS process. Current conditions of the site have not changed since the October 1991 site visit; therefore, the observations that were noted at that time are discussed.
The following observations were made during the October 1991 inspection:
- A security guard is stationed at the site 24 hours a day.
- Shallow, standing water was observed in the 3 ponds located within the EEA.
- Overpacked drums are being stored on a concrete decontamination pad that was built within the EEA.
- There are a number of empty, above ground plastic swimming pools within the EEA that had been used to store water purged from monitoring wells.
- Strong chemical odors were detected at 2 locations within the EEA: at a seep downgradient from pond PO1 and at an interceptor trench in the Sedge Meadow area.
- There were no signs that the site had been recently trespassed upon.
Site trespass posed a problem on the site in the past. The MSGS site was used for recreational purposes by all-terrain-vehicle (ATV) riders, motorcyclists, and occasionally by hunters. There were occasions on which relatively large numbers of ATV riders were observed on the site. The Maryland State Police were summoned on several occasions to escort trespassers from the site. Before site access was restricted, there were reports of equipment being vandalized on the site. This equipment included test well covers and vehicles that were being used for site remediation.
Dirt roads that enter the WEA from Marley road have been blocked with mounded soil and ditches to prevent site access by dirt bikes and ATVs.
As of December 17, 1993, site conditions had changed. New monitoring wells have been drilled at the EEA. Borehole investigations have been conducted at 3 locations of the site. Removal of site sludges is pending.
C. DEMOGRAPHICS, LAND USE, AND NATURAL RESOURCE USE
Demographics
Based on the 1990 Census, Cecil county has a total population of 71,347 people. A total of
94.5% of this population is white, 4.5% of the population is black, and the remaining 1% is of
mixed racial origin. The median age for the county
population based on the 1990 Census is 32.6
years, up from 29.6 years in 1980. Approximately 27% of the population is under age 18, 62%
are 18 to 64 years of age, and 10% are greater than 65 years. The average population density of
Cecil County is 205 persons per square mile. Elkton, a town of 9,073 residents (1990 Census
report), is about 3 miles east of the site. The town of North East is about 2 miles southwest of
the site and has a population of 1,913 people (1990 Census).
Land Use
The area around the site is zoned primarily for low and medium density residential development.
There are approximately 150 residences, housing about 575 persons within a 1-mile radius of the
site. All of these residences depend on groundwater for their source of potable water. Some of
the land near the site is also zoned for general commercial and industrial development. An
industrial park is located about 1.5 miles east-north east of the site.
Private residences border the Western Excavated Area (WEA) along Marley Road. Residences are also found north of the site along Marley and Nottingham Roads, with the closest residences found 600 to 800 feet from the EEA. A YMCA is located approximately 0.5 miles south of the site along Route 40.
A considerable amount of land near the site is also used for agricultural purposes, including both cropland and pasture.
Natural Resource Use
Residential and commercial users of groundwater in Cecil County draw water from two major
aquifers (an aquifer is permeable rock or other material through which water moves below the
earth's surface). The upper aquifer is called the Potomac Group and consists of unconsolidated
sediments of sand, gravel, silt, and clay. The lower aquifer is fractured bedrock. The State of
Maryland water well database reveals that 259 wells were installed in the vicinity of MSGS
(about 0.8 miles north, 1.9 miles east, 1 mile south, and 1 mile west) from 1969 to 1986 (5).
Most of the wells (142) were screened in the Potomac Group at depths ranging from 37 to 215
feet. The rest include deeper bedrock wells and shallow dug wells and range from 20 to 500 ft.
deep.
Two large groundwater users within 2 miles of MSGS include the Thiokol Chemical Company, about 1.5 miles east of the site, and the Town and Country Mobile Park, about 0.8 miles west of the site. The town of Elkton obtains most of its public water supply from surface water, but also uses 2 wells (5). Both wells are more than 4 miles east of the site. The town of North East uses surface water (from Little Northeast Creek) exclusively for its public water supply.
Much of the land in the area around the site is forested. The boundary of Elk Neck State Forest lies about 1 mile south of the site. Mill Creek, which receives surface runoff from the site, is not used for recreational fishing because it is too small to support game fish (4,7).
Available health data bases can be used to determine whether or not certain health effects occur more frequently in Cecil County than in the State of Maryland as a whole. This section describes these data bases; evaluation of the data bases occurs in the Public Health Implications section of this document.
DHMH is currently in the process of gathering cancer incidence data dating back to 1983. Comparative cancer incidence data (the number of new cancer cases diagnosed during a given time period) for the local (zip-code or census tract), county, and state levels are projected to be available in the future.
The birth defects registry at DHMH has incidence data available for the period 1984 to 1988; however, the data are limited to 13 sentinel birth defects that are reportable by law. These data are available at the county level.
Vital statistics (births and deaths) reports are available for Maryland counties from the early
1960s through 1987.
Two public meetings have been held to address concerns of residents living in the vicinity of the MSGS site. On September 20, 1989, a public meeting was held concerning drum removal at the site. Although the meeting was attended by representatives from MDE and EPA, no one from the community attended.
A second public hearing, held on June 25, 1990, was attended by twenty-five members of the community. A brief presentation was made that included the site history and an explanation of the remediation plans. There were no public health concerns expressed by members of the community who attended the meeting. Officials with the Cecil County Health Department were contacted in October 1991, but they were unaware of any community health concerns.
Local residents have expressed site-related health concerns in the past. In EPA's Preliminary Assessment of the site, it was noted that local citizens had complained of "odors and resulting health problems" (1). In 1976, local residents filed a lawsuit against Galaxy Chemicals Company and Maryland Sand and Gravelstone Company for alleged damages from odors emitted from the site (1,2). It was also noted that state inspectors complained of eye and throat irritation from exposure to airborne contaminants during site visits in May 1976 and again in July 1979.
This public health assessment was released for public comment from January 25, 1993, to February 26, 1993. Health-related questions and concerns that were received during the public comment period on the draft public health assessment for the MSGS site are addressed in Appendix B of this document.
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